For image capturing apparatuses such as a digital camera, precise removal of noise components has been sought due to demands from users for higher sensitivity and higher pixel counts.
As a conventional noise removal method, for example, Japanese Patent Laid-Open No. 2008-015741 discloses a method in which the input signal is divided into a plurality of frequency bands, noise removal and edge preservation are performed on the high frequency component, and the resultant high frequency component is combined with the low frequency component.